Shell and Tube Heat Exchangers in Distilleries

Background 

Sacome Shell and Tube Heat Exchangers have been adopted as the standard for cooling wort in most grain distilleries in Scotland.   

Since its formation in 1978 Sacome set out to be the most technically advanced manufacturer of Shell and Tube Heat Exchangers, or more simply Tubular Heat Exchangers, in the world. Today this goal is being realised and the use of Sacome technology in Scotland's distilleries is a good example.

Distilleries are renowned for their attention to detail in their manufacturing processes because the end product, the whiskies that are enjoyed the world over, have individual characteristics that need to be replicated batch after batch and year after year.

Choice of technology

There are two types of Heat Exchanger employed in the food and beverage industries; the Plate Heat Exchanger and the Shell and Tube Heat Exchanger.  Wort is the trade name given to the liquor that is the result of boiling malted barley in water, prior to fermentation.  It is a hot liquor that needs to be cooled quickly to preserve flavours, prevent bacterial contamination and make way for the next batch.

The liquor as it is drawn off contains the spend grains which gives it both a high solids content and a sweet sticky liquor.  These characteristics make it particularly unsuitable for plate type heat exchangers which would quickly block which is much less of a problem with Shell and Tube Heat Exchangers.

Heat Exchanger being off-loaded

Design considerations

The Shell and Tube Heat Exchanger has to rapidly cool the wort from around 63˚C to 20˚C.; To further complicate matters there may typically be a number of different sources of cooling water, for example, cooling tower water, fresh water and chilled water.  The climate in Scotland can be very cold in winter and the design of the system has to make use of different water sources to reduce cost wherever possible.

Another important consideration in the design is the requirement the temperature of the cooling water, after it has done its job should not rise above 45˚C as this water is used elsewhere in the process.

The Heat Exchanger illustrated was designed to process between 150 m3 and 250m3 of wort per hour.  The cooling water flows are between 120 m3 and 150 m3 at temperatures between 5˚C and 26˚C.

Factory Acceptance Test

The layout of the tubes on the support frame allow for complete draining of the system after final CIP (Clean in Place). This is important because of the severe winter weather and the risk of freezing.

Also illustrated is the expansion joint which is very complex technology to deal with the contraction and expansion due to fluctuating temperatures and pressures.

The final piece of the design brief was a requirement that the Heat Exchanger should be designed around a fatigue analysis with a twenty year time horizon. 

The outcome 

Sacome took the design brief and working closely with the technical experts and engineers in the distilleries refined the product and achieved the desired result.  It is hardly surprising that Sacome is the first choice for distillers in the UK. 

References:

Allied Distillers
Diageo
United Distillers
William Grant and Sons
McKay Invergordon Distillers
North British Distillers
Suntori Morrison Bowmore Distillers

 Heat Exchanger in situ